1. Field of the Invention
The present invention relates to a method and apparatus for controlling an engine, and especially to a method and apparatus for controlling an engine by providing a signal indicative of a desired engine output level to an engine control means such as an electronically controlled throttle valve.
2. Related Art
One prior art method of actively controlling the drive shaft torque of an automobile is disclosed in JP-A-2-201061 (1986).
This control method comprises preliminarily storing a target drive shaft torque pattern depending upon the vehicle speed and the accelerator pedal position in a memory or the like; determining a target drive shaft torque value from the current vehicle speed and accelerator pedal position, determining a target engine torque value from the target drive shaft torque and the gear ratio of a transmission and controlling the throttle valve opening so that the target engine torque value is obtained.
This control method aims at providing the acceleration which satisfies the driver's taste or at which driving is easy by using such a target drive shaft torque curve
However, the throttle valve opening in such prior art is independent of the operating conditions in which the vehicle is operate, while the vehicle speed is dependent on the accelerator pedal position, when the vehicle environment changes (for example the vehicle moves from lower elevations to higher elevations, or a heavy load is placed on the vehicle), a constant acceleration cannot be obtained even if the vehicle speed is dependent on the accelerator pedal position. An acceleration which satisfied the driver's taste or at which driving is easy can not be obtained.